"""
STER-GI Idea 3: Denoise-to-Sibling (去噪造兄弟)
================================================
- Train unconditional diffusion on ALL building property vectors (no labels)
- Generate "sibling" buildings via SDEdit (partial noise + denoise)
- Contrastive learning on (original, sibling) pairs
- Zero-shot evaluation on test pairs: encode → cosine sim → threshold → match

Baselines:
  - real-only (raw property cosine): no training at all
  - Idea 3 (denoise-to-sibling): diffusion + contrastive
"""

import os, sys, time, warnings, argparse
import numpy as np
import joblib, pickle as pkl
import torch, torch.nn as nn, torch.nn.functional as F
from torch.utils.data import DataLoader, TensorDataset
from sklearn.preprocessing import StandardScaler
from sklearn.metrics import precision_score, recall_score, f1_score, average_precision_score
from collections import defaultdict

warnings.filterwarnings("ignore")

# ============================================================
# Config
# ============================================================
PROPERTY_NAMES = [
    "bounding_box_width", "bounding_box_length", "area", "perimeter",
    "perimeter_ind", "volume", "convex_hull_area", "convex_hull_volume",
    "ave_centroid_distance", "height_diff", "num_floors", "axes_symmetry",
    "compactness_2d", "compactness_3d", "density", "elongation",
    "shape_ind", "hemisphericality", "fractality", "cubeness",
    "circumference", "aligned_bounding_box_width", "aligned_bounding_box_length",
    "aligned_bounding_box_height", "num_vertices"
]

CFG = {
    'diffusion_steps': 1000,
    'diffusion_hidden': 256,
    'diffusion_layers': 4,
    'diffusion_epochs': 500,
    'diffusion_lr': 1e-3,
    'diffusion_batch_size': 512,
    # SDEdit: how much noise to add (0=none, 1000=full)
    'sdedit_t0': 200,
    'num_siblings': 3,
    # Encoder
    'encoder_hidden': 128,
    'encoder_dim': 64,
    'contrastive_epochs': 200,
    'contrastive_lr': 1e-3,
    'contrastive_temp': 0.07,
    'contrastive_batch': 1024,
    # Eval: threshold sweep
    'eval_thresholds': [0.5, 0.6, 0.7, 0.75, 0.8, 0.85, 0.9, 0.92, 0.95, 0.97, 0.99],
    'device': 'cuda' if torch.cuda.is_available() else 'cpu',
}

# ============================================================
# Data: Extract property vectors
# ============================================================
def extract_vectors(prop_dict, source, id_list=None):
    """Extract property matrix for given source ('cands'/'index') and optional id filter"""
    first_prop = PROPERTY_NAMES[0]
    all_ids = list(prop_dict[first_prop][source].keys()) if id_list is None else id_list
    X = np.zeros((len(all_ids), len(PROPERTY_NAMES)), dtype=np.float32)
    valid_ids = []
    for i, bid in enumerate(all_ids):
        vec = []
        ok = True
        for pname in PROPERTY_NAMES:
            val = prop_dict[pname][source].get(bid, None)
            if val is None or (isinstance(val, float) and np.isnan(val)):
                val = 0.0
            vec.append(float(val))
        X[i] = vec
        valid_ids.append(bid)
    return X, valid_ids


def load_all_train_vectors(seed):
    """Load property vectors for ALL training buildings (both cands and index)"""
    train_path = (f"data/property_dicts/Hague_allmodels_v1_train_matching_medium_"
                  f"neg_samples_num=2_vector_normalization=True_seed={seed}.joblib")
    prop = joblib.load(train_path)

    X_cands, ids_cands = extract_vectors(prop, 'cands')
    X_index, ids_index = extract_vectors(prop, 'index')
    X = np.concatenate([X_cands, X_index], axis=0)
    all_ids = ids_cands + ids_index
    print(f"Loaded {len(X)} train building vectors ({len(X_cands)} cands + {len(X_index)} index)")
    return X, all_ids, prop


def load_test_pairs(seed):
    """Load test pairs with labels: list of (cand_id, index_id, label)"""
    test_path = (f"data/property_dicts/Hague_allmodels_v1_test_matching_medium_"
                 f"neg_samples_num=2_vector_normalization=True_seed={seed}.joblib")
    prop = joblib.load(test_path)

    partition = pkl.load(open(f"data/dataset_partitions/Hague_seed{seed}.pkl", 'rb'))
    test_pairs = partition['test']['matching']['negative_sampling']['medium'][2]

    # Build cand/index ID -> vector mappings
    cand_map = {}
    for bid in prop[PROPERTY_NAMES[0]]['cands'].keys():
        vec = []
        for pname in PROPERTY_NAMES:
            val = prop[pname]['cands'].get(bid, None)
            if val is None or (isinstance(val, float) and np.isnan(val)):
                val = 0.0
            vec.append(float(val))
        cand_map[bid] = np.array(vec, dtype=np.float32)

    index_map = {}
    for bid in prop[PROPERTY_NAMES[0]]['index'].keys():
        vec = []
        for pname in PROPERTY_NAMES:
            val = prop[pname]['index'].get(bid, None)
            if val is None or (isinstance(val, float) and np.isnan(val)):
                val = 0.0
            vec.append(float(val))
        index_map[bid] = np.array(vec, dtype=np.float32)

    cand_vecs, index_vecs, labels = [], [], []
    for cid, iid in test_pairs:
        if cid in cand_map and iid in index_map:
            cand_vecs.append(cand_map[cid])
            index_vecs.append(index_map[iid])
            labels.append(1 if cid == iid else 0)

    cand_vecs = np.array(cand_vecs, dtype=np.float32)
    index_vecs = np.array(index_vecs, dtype=np.float32)
    labels = np.array(labels, dtype=np.int32)

    print(f"Test pairs: {len(labels)} ({labels.sum()} pos, {(1-labels).sum()} neg)")
    return cand_vecs, index_vecs, labels


# ============================================================
# Diffusion Model (DDPM on property vectors)
# ============================================================
class MLPDiffusion(nn.Module):
    def __init__(self, dim, hidden=256, layers=4):
        super().__init__()
        self.time_embed = nn.Sequential(
            nn.Linear(1, hidden), nn.SiLU(), nn.Linear(hidden, hidden))
        net = [nn.Linear(dim + hidden, hidden), nn.SiLU()]
        for _ in range(layers - 1):
            net += [nn.Linear(hidden, hidden), nn.SiLU()]
        net.append(nn.Linear(hidden, dim))
        self.net = nn.Sequential(*net)

    def forward(self, x, t):
        t_emb = self.time_embed(t.unsqueeze(-1).float())
        return self.net(torch.cat([x, t_emb], dim=-1))


class DiffusionScheduler:
    def __init__(self, steps=1000, beta_start=1e-4, beta_end=0.02):
        self.steps = steps
        self.betas = torch.linspace(beta_start, beta_end, steps)
        self.alphas = 1 - self.betas
        self.alpha_bars = torch.cumprod(self.alphas, dim=0)

    def add_noise(self, x0, t):
        ab = self.alpha_bars[t].view(-1, 1)
        noise = torch.randn_like(x0)
        return torch.sqrt(ab) * x0 + torch.sqrt(1 - ab) * noise, noise

    @torch.no_grad()
    def denoise_step(self, model, xt, t):
        """Single DDPM reverse step"""
        a = self.alphas[t].view(-1, 1)
        ab = self.alpha_bars[t].view(-1, 1)
        b = self.betas[t].view(-1, 1)
        eps = model(xt, t.float())
        x0_hat = (xt - torch.sqrt(1 - ab) * eps) / torch.sqrt(a)
        if t.min() == 0:
            return x0_hat
        ab_prev = self.alpha_bars[t - 1].view(-1, 1)
        mean = (torch.sqrt(ab_prev) * b / (1 - ab) * x0_hat +
                torch.sqrt(a) * (1 - ab_prev) / (1 - ab) * xt)
        var = b * (1 - ab_prev) / (1 - ab)
        return mean + torch.sqrt(var) * torch.randn_like(xt)

    @torch.no_grad()
    def sdedit(self, model, x0, t0, device):
        """Add noise to t0, then denoise back → sibling"""
        n = x0.shape[0]
        t0_t = torch.full((n,), t0, device=device, dtype=torch.long)
        ab_t0 = self.alpha_bars[t0]
        noise = torch.randn_like(x0)
        xt = torch.sqrt(ab_t0) * x0 + torch.sqrt(1 - ab_t0) * noise
        for t in range(t0, -1, -1):
            tb = torch.full((n,), t, device=device, dtype=torch.long)
            xt = self.denoise_step(model, xt, tb)
        return xt


# ============================================================
# Contrastive Encoder
# ============================================================
class BuildingEncoder(nn.Module):
    def __init__(self, dim, hidden=128, out_dim=64):
        super().__init__()
        self.net = nn.Sequential(
            nn.Linear(dim, hidden), nn.BatchNorm1d(hidden), nn.ReLU(),
            nn.Linear(hidden, hidden), nn.BatchNorm1d(hidden), nn.ReLU(),
            nn.Linear(hidden, out_dim))

    def forward(self, x):
        return F.normalize(self.net(x), dim=-1)


def info_nce_loss(embs, temp=0.07):
    """embs: [2B, D] where (0,1), (2,3)... are positives"""
    n = embs.shape[0] // 2
    sim = embs @ embs.T / temp
    # Mask self
    sim = sim.masked_fill(torch.eye(2 * n, device=embs.device, dtype=torch.bool), -1e9)
    # Labels: for row i, positive is i^1 (flip last bit)
    labels = torch.arange(2 * n, device=embs.device)
    labels = labels ^ 1  # (0->1, 1->0, 2->3, 3->2, ...)
    return F.cross_entropy(sim, labels)


# ============================================================
# Training
# ============================================================
def train_diffusion(X, device):
    print("\n" + "=" * 50)
    print("Stage 1: Train Diffusion on Building Vectors")
    print("=" * 50)
    dim = X.shape[1]
    model = MLPDiffusion(dim, CFG['diffusion_hidden'], CFG['diffusion_layers']).to(device)
    sched = DiffusionScheduler(CFG['diffusion_steps'])
    sched.betas = sched.betas.to(device)
    sched.alphas = sched.alphas.to(device)
    sched.alpha_bars = sched.alpha_bars.to(device)

    opt = torch.optim.Adam(model.parameters(), lr=CFG['diffusion_lr'])
    ds = TensorDataset(torch.FloatTensor(X))
    dl = DataLoader(ds, batch_size=CFG['diffusion_batch_size'], shuffle=True)

    model.train()
    for ep in range(CFG['diffusion_epochs']):
        total = 0
        for (xb,) in dl:
            xb = xb.to(device)
            bs = xb.shape[0]
            t = torch.randint(0, CFG['diffusion_steps'], (bs,), device=device)
            xt, noise = sched.add_noise(xb, t)
            loss = F.mse_loss(model(xt, t.float()), noise)
            opt.zero_grad()
            loss.backward()
            opt.step()
            total += loss.item() * bs
        if (ep + 1) % 100 == 0:
            print(f"  Epoch {ep+1}/{CFG['diffusion_epochs']} | Loss: {total/len(ds):.6f}")
    print(f"  Done. Final loss: {total/len(ds):.6f}")
    return model, sched


def generate_siblings(model, sched, X, device):
    print("\n" + "=" * 50)
    print(f"Stage 2: Generate Siblings (t0={CFG['sdedit_t0']})")
    print("=" * 50)
    model.eval()
    origs, sibs = [], []
    bs = CFG['diffusion_batch_size']
    for i in range(0, len(X), bs):
        xb = torch.FloatTensor(X[i:i+bs]).to(device)
        for _ in range(CFG['num_siblings']):
            sib = sched.sdedit(model, xb, CFG['sdedit_t0'], device)
            origs.append(xb.cpu().numpy())
            sibs.append(sib.cpu().numpy())

    origs = np.concatenate(origs, axis=0)
    sibs = np.concatenate(sibs, axis=0)
    l2 = np.mean(np.linalg.norm(origs - sibs, axis=1))
    print(f"  Generated {len(origs)} pairs | Mean L2 diff: {l2:.4f}")
    return origs, sibs


def train_encoder(origs, sibs, device):
    print("\n" + "=" * 50)
    print("Stage 3: Contrastive Encoder Training")
    print("=" * 50)
    dim = origs.shape[1]
    encoder = BuildingEncoder(dim, CFG['encoder_hidden'], CFG['encoder_dim']).to(device)
    opt = torch.optim.Adam(encoder.parameters(), lr=CFG['contrastive_lr'])

    # Interleave: [orig1, sib1, orig2, sib2, ...]
    n = len(origs)
    data = np.zeros((n * 2, dim), dtype=np.float32)
    data[0::2] = origs
    data[1::2] = sibs
    ds = TensorDataset(torch.FloatTensor(data))
    dl = DataLoader(ds, batch_size=CFG['contrastive_batch'], shuffle=True)

    encoder.train()
    for ep in range(CFG['contrastive_epochs']):
        total = 0
        for (xb,) in dl:
            xb = xb.to(device)
            emb = encoder(xb)
            loss = info_nce_loss(emb, CFG['contrastive_temp'])
            opt.zero_grad()
            loss.backward()
            opt.step()
            total += loss.item() * xb.shape[0]
        if (ep + 1) % 50 == 0:
            print(f"  Epoch {ep+1}/{CFG['contrastive_epochs']} | Loss: {total/len(ds):.4f}")
    print(f"  Done. Final loss: {total/len(ds):.4f}")
    return encoder


# ============================================================
# Evaluation
# ============================================================
@torch.no_grad()
def eval_zero_shot(encoder, cand_vecs, index_vecs, labels, device, tag="Model"):
    """Zero-shot pair classification via cosine similarity"""
    encoder.eval()
    ct = torch.FloatTensor(cand_vecs).to(device)
    it = torch.FloatTensor(index_vecs).to(device)
    ce = encoder(ct).cpu().numpy()
    ie = encoder(it).cpu().numpy()

    # Cosine sim for each pair
    sims = np.sum(ce * ie, axis=1)  # [N]

    # Sweep thresholds
    best_f1, best_thresh, best_res = 0, 0.5, None
    for th in CFG['eval_thresholds']:
        pred = (sims >= th).astype(np.int32)
        p = precision_score(labels, pred, zero_division=0)
        r = recall_score(labels, pred, zero_division=0)
        f = f1_score(labels, pred, zero_division=0)
        if f > best_f1:
            best_f1, best_thresh, best_res = f, th, (p, r, f)

    print(f"\n  {tag} (best threshold={best_thresh:.2f}):")
    print(f"    Precision: {best_res[0]:.4f}")
    print(f"    Recall:    {best_res[1]:.4f}")
    print(f"    F1:        {best_res[2]:.4f}")

    # Also AP score
    ap = average_precision_score(labels, sims)
    print(f"    AvgPrecision: {ap:.4f}")

    return {'precision': best_res[0], 'recall': best_res[1], 'f1': best_res[2],
            'ap': ap, 'threshold': best_thresh}


def eval_real_only(cand_vecs, index_vecs, labels):
    """Baseline: raw property cosine similarity, no training"""
    # Normalize
    cn = cand_vecs / (np.linalg.norm(cand_vecs, axis=1, keepdims=True) + 1e-8)
    i_n = index_vecs / (np.linalg.norm(index_vecs, axis=1, keepdims=True) + 1e-8)
    sims = np.sum(cn * i_n, axis=1)

    best_f1, best_thresh, best_res = 0, 0.5, None
    for th in CFG['eval_thresholds']:
        pred = (sims >= th).astype(np.int32)
        p = precision_score(labels, pred, zero_division=0)
        r = recall_score(labels, pred, zero_division=0)
        f = f1_score(labels, pred, zero_division=0)
        if f > best_f1:
            best_f1, best_thresh, best_res = f, th, (p, r, f)

    ap = average_precision_score(labels, sims)
    print(f"\n  Baseline Real-Only (best th={best_thresh:.2f}):")
    print(f"    P={best_res[0]:.4f} R={best_res[1]:.4f} F1={best_res[2]:.4f} AP={ap:.4f}")

    return {'precision': best_res[0], 'recall': best_res[1], 'f1': best_res[2],
            'ap': ap, 'threshold': best_thresh}


# ============================================================
# Main
# ============================================================
def main():
    parser = argparse.ArgumentParser()
    parser.add_argument('--seed', type=int, default=1)
    parser.add_argument('--t0', type=int, default=200, help='SDEdit noise level')
    parser.add_argument('--skip_diff', action='store_true')
    parser.add_argument('--skip_enc', action='store_true')
    args = parser.parse_args()

    CFG['sdedit_t0'] = args.t0
    device = CFG['device']
    seed = args.seed
    print(f"Device: {device} | t0: {args.t0} | Seed: {seed}")

    # ---- Load data ----
    X_train, train_ids, train_prop = load_all_train_vectors(seed)
    cand_vecs, idx_vecs, labels = load_test_pairs(seed)

    # Normalize (fit on train, apply to test)
    scaler = StandardScaler()
    X_train_s = scaler.fit_transform(X_train)
    cand_s = scaler.transform(cand_vecs)
    idx_s = scaler.transform(idx_vecs)

    # ---- Stage 1+2: Diffusion → Siblings ----
    diff_path = f"saved_model_files/diff_idea3_s{seed}_t{args.t0}.pt"
    sib_path = f"saved_model_files/siblings_idea3_s{seed}_t{args.t0}.npz"

    if args.skip_diff and os.path.exists(diff_path):
        print(f"Loading cached diffusion model: {diff_path}")
        ck = torch.load(diff_path, map_location=device)
        model = MLPDiffusion(X_train_s.shape[1], CFG['diffusion_hidden'],
                            CFG['diffusion_layers']).to(device)
        model.load_state_dict(ck['model'])
        sched = DiffusionScheduler(CFG['diffusion_steps'])
        sched.betas = sched.betas.to(device)
        sched.alphas = sched.alphas.to(device)
        sched.alpha_bars = sched.alpha_bars.to(device)
    else:
        model, sched = train_diffusion(X_train_s, device)
        torch.save({'model': model.state_dict()}, diff_path)

    if os.path.exists(sib_path):
        print(f"Loading cached siblings: {sib_path}")
        data = np.load(sib_path)
        origs, sibs = data['origs'], data['sibs']
    else:
        origs, sibs = generate_siblings(model, sched, X_train_s, device)
        np.savez_compressed(sib_path, origs=origs, sibs=sibs)

    # ---- Stage 3: Contrastive Encoder ----
    enc_path = f"saved_model_files/enc_idea3_s{seed}_t{args.t0}.pt"

    if args.skip_enc and os.path.exists(enc_path):
        print(f"Loading cached encoder: {enc_path}")
        ck = torch.load(enc_path, map_location=device)
        encoder = BuildingEncoder(X_train_s.shape[1], CFG['encoder_hidden'],
                                  CFG['encoder_dim']).to(device)
        encoder.load_state_dict(ck['encoder'])
    else:
        encoder = train_encoder(origs, sibs, device)
        torch.save({'encoder': encoder.state_dict()}, enc_path)

    # ---- Evaluation ----
    print("\n" + "=" * 50)
    print("RESULTS")
    print("=" * 50)

    r_base = eval_real_only(cand_s, idx_s, labels)
    r_idea3 = eval_zero_shot(encoder, cand_s, idx_s, labels, device,
                              f"Idea 3 (t0={args.t0})")

    print("\n" + "=" * 50)
    print(f"SUMMARY (seed={seed}, t0={args.t0})")
    print("=" * 50)
    print(f"  Baseline (real-only):    F1={r_base['f1']:.4f}  AP={r_base['ap']:.4f}")
    print(f"  Idea 3  (denoise-sib):   F1={r_idea3['f1']:.4f}  AP={r_idea3['ap']:.4f}")
    print(f"  ΔF1: {r_idea3['f1'] - r_base['f1']:.4f}  ΔAP: {r_idea3['ap'] - r_base['ap']:.4f}")

    return r_base, r_idea3


if __name__ == '__main__':
    main()